Vascular disease and Alzheimer’s disease: common links

There is growing evidence linking vascular disease and Alzheimer’s disease, and we’ve heard this afternoon at the Alzheimer’s Research UK Conference about research that seeks to understand these links. Vascular disease and Alzheimer’s have many risk factors in common, and we’re increasingly seeing that what’s good for the heart is good for the brain. It’s been known for a long time that a good supply of blood to the brain is important to keep it functioning well. However, researchers want to understand more about the changes that occur in blood vessels in the brain during Alzheimer’s, and how these changes contribute to the disease.

Amyloid in the blood vessels

Prof James Nicoll from the University of Southampton spoke about some of the common risk factors for vascular disease and Alzheimer’s disease – risk factors such as obesity, diabetes, high blood pressure and high cholesterol. News about Prof Nicoll’s talk hit the headlines earlier this week, and you can read more about his research on our website.

He and his team are working to better understand the changes in blood vessels that occur as Alzheimer’s develops, and their work focuses on the effects of amyloid – a protein that accumulates in the brain in Alzheimer’s disease – on the brain’s vascular system. They’ve shown that not only does amyloid build-up occur around brain cells, but the protein is also deposited along the lining of blood vessel walls in the brain, damaging smooth muscle cells in the process. These cells play a critical role in helping to distribute blood flow within the brain at a microscopic level, directing the blood supply to particular nerve cells as needed. Prof Nicoll’s team believes that the damage to these cells may interfere with this important process.

Learning from past trials

His talk also touched on results of a study that has followed participants of a decade-old trial of a vaccine designed to remove amyloid from the brain. Trials of the treatment, AN1792, were halted after people in the study developed side effects, but in the years following, Prof Nicoll and his team have sought to understand how the treatment affected the brain. The research outlined in today’s talk shows that although the vaccine was successful in removing amyloid from brain cells, the protein was deposited along the blood vessels walls as it travelled out of the brain, where Prof Nicoll argues it may have caused further damage. This work could have implications for trials of new treatments that target amyloid, and it’s hoped these results will help to inform these studies. Findings like these also demonstrate how important it is for people to get involved in research.

We also heard from Prof Karen Horsburgh, from the University of Edinburgh, who presented some of her research investigating how problems with the brain’s blood vessels relate to other brain changes seen in Alzheimer’s. Previous research from her team has shown that a decrease in blood flow to the brain is linked to cognitive decline. Her lab is now trying to better understand the links between impaired blood flow and changes in the brain that are seen in Alzheimer’s, such as the build-up of amyloid.

Inflammatory response

Her results show that reduced blood flow and amyloid tend to be found alongside markers of inflammation. Inflammation is a hot topic in Alzheimer’s research at present: recent studies have found that certain genes involved in the immune response are linked to an increased risk of the disease. These discoveries kick-started an explosion in research to understand the role of inflammation in Alzheimer’s, and   on this topic yesterday. Dr Horsburgh’s results suggest that impaired blood flow and amyloid build-up may work together to trigger a damaging inflammatory response, and her team is now working to investigate this theory further. As part of this work, they are looking at potential ways of stopping this damage with drugs designed to improve blood circulation.

By working to understand how changes in blood vessels contribute to Alzheimer’s, these researchers are shedding new light on the disease, and their findings could help guide the search for new treatments and preventions. In the meantime, their work highlights the importance of good vascular health for helping protect the brain. While we don’t yet have sure-fire preventions for Alzheimer’s, we can reduce our risk of the disease and it’s a good idea to keep healthy with regular exercise, a healthy diet, and by keeping weight and blood pressure in check. You can check out the dementia information section of our website for more advice on reducing dementia risk.